Solution:
Since, 20 pillars are connected by beams with all its non adjacent pillars.
Total number of beams
Suppose that 20 pillars of the same height have been erected along the boundary of a circular stadium. If the top of each pillar has been connected by beams with the top of all its non-adjacent pillars,then the total number of beams is :
Since, 20 pillars are connected by beams with all its non adjacent pillars.
Total number of beams